Discovering your big toenails have turned black can be unsettling. While a dark discoloration sometimes indicates a serious underlying condition, it is often due to less concerning factors. Understanding the various reasons behind this change is the first step toward addressing it. This article explores common causes of black toenails, guidance on when medical attention might be needed, and practical advice for maintaining toenail health.
Common Reasons for Black Toenails
Trauma frequently causes black toenails, known as a subungual hematoma. This occurs when blood vessels beneath the nail rupture, causing blood to collect under the nail plate. Injuries can result from direct impact, like stubbing a toe or dropping an object, or from repetitive stress. Activities such as running with ill-fitting shoes, which cause the big toe to repeatedly strike the shoe’s front, can also lead to this bruising. The pooled blood appears black or dark red and typically grows out with the nail over several months.
Fungal infections (onychomycosis) can cause toenail discoloration, sometimes appearing dark brown or black. While often white or yellow, debris accumulation under the nail can lead to a darker hue. Fungi thrive in warm, moist environments, making toenails susceptible. Symptoms might also include nail thickening, brittleness, or an unpleasant odor.
Melanin production can cause dark streaks or patches on the toenail, a condition called melanonychia. This occurs when pigment-producing cells in the nail matrix deposit melanin into the nail plate. Benign causes include natural racial pigmentation, certain moles, or pigment cell activation due to trauma. However, a new or changing dark streak can rarely signal subungual melanoma, a serious skin cancer developing under the nail. This melanoma is uncommon but requires identification if the streak is irregular, rapidly changing, or extends to the surrounding skin.
Certain medications can induce nail discoloration as a side effect. Some chemotherapy drugs, antimalarials, and specific antibiotics can cause changes in nail color, including darkening. These changes may manifest as brown or black bands and affect one or multiple nails. If you are on medication and notice nail discoloration, consult your healthcare provider.
When to Seek Medical Advice
While many black toenails are harmless and resolve on their own, certain signs indicate medical evaluation is needed. Consult a healthcare professional if discoloration appears without any known injury or worsens over time. An unexplained black toenail could point to an underlying issue that requires professional attention.
Pain, swelling, or other signs of infection like redness or pus around the nail warrant immediate medical advice. These symptoms suggest a potential bacterial infection or severe nail bed injury. If the nail detaches or the dark spot changes color or size, a medical professional should assess it.
A concerning sign is a dark streak extending from the nail plate onto the cuticle or surrounding skin, known as Hutchinson’s sign. This indicates subungual melanoma, a rare but serious skin cancer. Additionally, if multiple nails are affected without clear cause, or if you have underlying health conditions like diabetes or poor circulation, seek medical advice for any toenail changes.
Maintaining Toenail Health
Proper footwear prevents black toenails, especially those caused by trauma. Wearing well-fitting shoes with ample toe room is crucial, particularly during physical activity. Shoes that are too tight cause constant pressure, while loose ones allow the foot to slide forward, leading to repetitive impact on the big toe. Try on shoes later in the day when feet are slightly swollen to ensure a comfortable fit.
Correct nail trimming techniques prevent issues. Toenails should be trimmed straight across, not too short, and without rounding corners. This prevents ingrown toenails and reduces the likelihood of the nail pressing against the shoe. Regular trimming ensures that longer nails do not repeatedly come into contact with footwear, which can lead to trauma.
Maintaining good foot hygiene prevents fungal infections. Keeping feet clean and dry is essential. Wearing moisture-wicking socks can help manage sweat and reduce dampness.
Protecting your feet in environments where injury is possible also prevents black toenails. Wearing protective footwear, such as steel-toed boots, can shield toes from accidental impact. Regularly inspecting toenails for changes, like new discoloration or tenderness, allows for early detection of potential problems.